The performance of data storage systems inevitably varies over the course of a lifetime. Performance is affected by several different factors, including the types of components employed in the storage system, the operational settings, and a customer's storage requirements, such as capacity and I/O demand. As components fail or become over- or under-utilized, performance might suffer. If the operational settings are improper for the customer's storage configuration, performance might be degraded. If the customer imposes storage demands which are too rigorous for the present system, resulting in overburdening the storage system, performance will be adversely affected.
These performance-affecting factors vary during the life of the data storage system. Moreover, the factors might vary dramatically in the short term. When performance noticeably changes, the user is often tempted to make system alterations that are expected or believed to improve performance. However, the alterations might be based on perceived problems which are actually symptoms of a more fundamental hidden problem. This type of uninformed problem solving might lead the user to incur unnecessary costs and system down time without ever satisfactorily improving performance. For instance, the user might believe that adding another disk drive to the disk array would improve performance, when in reality, performance could be improved by simply reconfiguring the data storage system in a new manner which better accommodates the user's evolving storage demands.
It would therefore be advantageous to evaluate system performance during operation in an effort to monitor or anticipate situations which adversely impact performance. Once detected, the customer could then be alerted that the system is not performing optimally, and instructed as to what could be done to improve performance.